# Module Syscall_result_intf

    module Syscall_result_intf: sig .. end

This returns a preallocated object for all errors and at least a few `ok_value`s, so can be used in many contexts where avoiding allocation is important.

    module type S = sig .. end

    module type Arg = sig .. end

This returns a preallocated object for all errors and at least a few `ok_value`s, so can be used in many contexts where avoiding allocation is important.
This is more efficient than calling `error_exn` and then the `create_error` of the destination type.
`to_int t` must be >= 0, otherwise `create_ok` will raise.